This invention relates to diazocopiers and, more particularly, to diazocopiers including apparatus for ensuring that the copies produced by the copier are as free from odors as possible.
In diazocopiers the developing medium is ammonia (NH.sub.3) which, as is well-known, has an unpleasant odor. It is, accordingly, desirable that as much ammonia vapor as possible be eliminated from the copy material before it exits the copier. Certain diazotype machines such as those disclosed in U.S. Pat. No. 4,059,405 (Barto et al), assigned to the assignee herein, include scavenging and neutralizing devices for eliminating ammonia fumes released in the development process. The disclosure of U.S. Pat. No. 4,059,405 is incorporated herein by reference.
One aspect of the odor problem which is associated with diazotype copiers results from the fact that the print medium, which in most instances is a fibrous material such as paper, absorbs ammonia vapors which are released to the air after the paper exits the copier. It has been found that heating this diazotype copy material after it has been developed serves to release entrapped ammonia vapors where they may be collected before exiting the copier. A number of attempts have been proposed for solving the entrapped ammonia vapor problem by heating the developed diazotype copy material.
One arrangement for post-development heating of the copy material is found in U.S. Pat. No. 4,371,247 (Hewelt et al) in which the copy material is heated via intimate contact with a heated roller after exiting the developing chamber. This arrangement has been found less than completely satisfactory, however, because the copy material must intimately contact the heating element which requires complex control over the heating element in order to avoid degrading the paper or overheating. This arrangement also requires a "wind-up" roller for assuring that the paper stays in close proximity to the heating roller.
Other arrangements for the post-development heating of the copy material may be found in U.S. Pat. Nos. 4,092,655 (Schroter) and 4,109,268 (Schroter) which disclose the use of infrared tubes to provide the heating. However, these arrangements have also been less than completely satisfactory because they also require complex control over the temperature of the infrared tubes and over the speed at whch the copy material is fed through the copier.